All wrapped up in plastics? Sorry, the evidence isn't there

By Patrick McIlheran of the Journal Sentinel

Published on: 4/29/2011

I whipped up a blog post the other day mentioning an article about a big new study of bisphenol A. The article was by Jon Entine in The American, a magazine put out by The American Enterprise Institute.

The study, commissioned by the German Society of Toxicology, looked at about 5,000 studies by other scientists of the chemical used to make plastics work better. It found that “[BPA] exposure represents no noteworthy risk to the health of the human population, including newborns and babies.”

Since then, questions have been raised about the independence of the study’s authors. The Journal Sentinel’s news department published an article guest-written by ex-Journal Sentinel reporter Susanne Rust, now working in California, which casts some doubt on the study.

As I sort through all this, something becomes plain: The idea that the German study is ruined because of what turn out to be a couple of tangential connections just doesn't stand up. The study, in fact, raises legitimate concerns about the overwrought reaction to BPA.

The study’s declaration of interest section is where the nine authors report anything that could lead to questions about their independence. Here's what it says:

“Dr. H. Schweinfurth: I am an employee of Bayer Schering Pharma, which is a division of Bayer AG. The Material Sciences division of Bayer AG is one of the producers and users of BPA. In my activities as a Nonclinical Advisor I am involved in the development of drugs for my employer, although I have no responsibilities for industrial chemicals such as BPA nor a direct relationship to the latter division.

“Prof. U. Gundert-Remy: In my capacity as the former head of the department responsible for human health risk assessment of chemicals at the governmental Federal Institute for Risk Assessment (BFR) in Germany, I have been involved in the EU risk assessment of bisphenol A.

“Dr. W. Völkel: I am an employee of the Bavarian Health and Food Safety Authority and responsible for the realization of biomonitoring studies and assessment of toxicological research and biomonitoring studies of chemicals such as bisphenol A. I have been involved in the following studies on BPA: Human exposure to bisphenol A by biomonitoring: Methods, results and assessment of environmental exposures (W. Dekant, W. Völkel. Toxicol Appl Pharmacol 2008;228:114–134). This study was supported in part by the Polycarbonate/BPA Global Group; this review represents the individual professional views of the authors and not necessarily the views of the Polycarbonate/BPA Global Group. The studies at the University of Würzburg (Chem Res Toxicol 2002;15:1281–1287; Drug Metab Dispos 2005;33:1748–1757) were supported by the German Umweltbundesamt using equipment provided by the Deutsche Forschungsgemeinschaft and the State of Bavaria. For the studies at the Bavarian Health and Food Safety Authority (Toxicol Lett 2008;179:155–162; Environ Res 2010; in press, doi:10.1016/j.envres.2010.10.001) and for the present study no external funding was obtained.

“The authors alone are responsible for the content and writing of the paper.”

If you were counting, that's two of nine authors with actual conflicts to report. The notion that the German study – peer reviewed and run by an independent, respected group consisting of a profession that had been notably cautious about BPA – is somehow industry propaganda just isn’t supported by the facts.

There are some key things to keep in mind.

One is that unless the German toxicologists lied in a peer-reviewed declaration of conflicts (which is unlikely, though not impossible), their paper isn’t industry propaganda. What's more, this was a survey of studies – they didn’t design the research but simply reviewed the work of other, independent scientists.

Another is that the Germans didn’t say it’s safe to dump BPA by the barrel, since that was never the question. Bisphenol leaches into water and foods from packaging, in minute amounts. The question is always whether the risk at the dose people are conceivably exposed to outweighs the benefit, given that the chemical is for now hard to replace. It’s a close question, and the Germans point out that aside from toxicology, countries can and do answer it politically, based on the public’s perception of risk. All they conclude is that, by the lights of toxicology, BPA probably isn’t harmful.

And finally, there’s this: Such studies shouldn’t surprise anyone. Read the Germans’ paper and what you’ll find is not an attack on scientists who earlier suggested BPA could be harmful. Rather, they evaluate one set of findings against another.

That’s how research works: New findings arrive. The notion that any report contrary to earlier findings must be motivated by foul intentions and needs discrediting makes sense only if you presume that knowledge on a given topic is complete and perfect. That's the attitude of politics, not science.